1. Field of the Invention
The prevent invention relates to a context-based adaptive binary arithmetic coding (CABAC) decoding device and a decoding method thereof, and particularly, to a context-based adaptive binary arithmetic coding (CABAC) decoding device for increasing a video decoding efficiency and reducing a hardware cost and a decoding method thereof.
2. Description of the Related Art
Yongseok Yi et al. disclosed a “high-speed H.264/AVC CABAC decoding” in Transactions on Circuits and Systems for Video Technology, IEEE, in April 2007 (hereinafter, referred to as Document 1). In Document 1, a decoding speed is enhanced in a pipelining way. However, in a decoding process, a selection of context models must be determined by a latest decoded bin value. To resolve this problem, a decoder needs on standby for two cycles until a previous bin is decoded, and then, performs a decoding procedure for next bin. Therefore, the speed of the decoder described in Document 1 can only reach 0.25 bin per cycle in average.
Pin-Chin Lin et al. disclosed a “branch selection multi-symbol high throughput CABAC decoder architecture for H.264/AVC” in proceedings of IEEE International Symposium on Circuits and Systems, in May, 2009 (hereinafter, referred to as Document 2). In Document 2, the problems of data dependency and memory access conflict in the decoding process are resolved and, all context models are stored in registers. However, since the registers for storing the context models requires a large area, it causes a large amount of hardware cost.
Moreover, in the technology disclosed in U.S. patent application Ser. No. 11/863,973 published on Oct. 9, 2008, two bins can be decoded in one cycle only when specific syntax elements are met. Under other circumstances, only one syntax element can be decoded in one cycle. Therefore, the speed of the decoder can only reach 0.80 bin per cycle in average.
In view of the above prior art disadvantages, the prevent invention provides a context-based adaptive binary arithmetic coding (CABAC) decoding device and a decoding method thereof which increases the decoding speed of the context-based adaptive binary arithmetic (CABAC) decoding device to meet the real-time decoding requirement of HD videos under the consideration of hardware cost.